High tension fuse with high rupturing power



March 1, 1938. L. J. SAUDICOEUR 2,109,850

HIGH TENSION FUSE WITH HIGH RUPTURING POWER Filed March 27, 1935 J0zzzrZ022 ezzz Patented Mar. 1, 1938 PATENT OFFICE HIGH TENSION FUSE WITHHIGH RUPTUR- INGP OWER

Louis Joseph Saudicoenr, Villeurbanne, France,

assignor to Ateliers de Constructions Electriques de Belle, Paris,France Application March 27, 1935, Serial No. 13,250 In Germany May 8,1933 2 Claims.

Safety fuses are known for operation at high tensions having a highrupturing power comprising essentially a fusible wire disposed within acylinder of insulating material filled with a 5 substance which iselectrically inert. Such devices have the following disadvantages. Thefusible wire of very small diameter subjected to high voltage becomesluminous due to the production of corona discharges, oxidizes anddeteriorates. Moreover if the interruption of heavy currents may to acertain extent be suitably effected, it is not the same with currents ofsmall intensity which cannot be interrupted.

The present invention permits of completely overcoming thesedisadvantages. It has for its object a high tension safety fusecomprising a fusible wiredisposed in an insulating cylinder containingan electrically inert material and is characterized in that the fusiblewire is covered with insulating varnish or other insulating materialfulfilling the same object and is in part wound in a helix on aninsulating support enclosed or embedded in the inert material, theremainder of the wire being disposed in the part of the cylindercontaining only air or inert material in such manner as not to contactwith the said insulating support. Other characteristics will appear fromthe following description of the invention. to The accompanying drawingillustrates diagrammatically in elevation partly in section a fuseconstructed in accordance with the invention. The fusible wire isdenoted by I. It is disposed on an insulating support constituted by aglass tube 2. The whole is enclosed in a cylinder 3 containing an inertmaterial consisting of sand or like material. This material is held inthe cylinder by caps 5 which may either seal it her-' 40 metically orpermit communication with the exterior through the medium of perforatedplates 1 or the like.

In accordance with the invention the wire I is covered with varnish orinsulating material and woundlnahelixoverpartofitslengthontheglasstubei; theremainderofthewireisspaced from the glassandstretched'inthe air. For

this purpose the fusible wire may be passed into the interior of theglass tube which contains only air and it is held straight in this partof "its length.

The winding in a helix of the fusible wire permits of avoiding coronadischarges. On the other hand the covering of varnish or insulatingmaterial prevents the oxidation of this wire. A glow discharge isavoided over the lower straight part of the wire by metallizing theouter, inner or both walls of the cylinder 3 as shown exaggerated at 5.Such an arrangement becomes in effect the same as enclosing the straightwire in a Faraday cage.

The arrangement described permits of completely avoiding deteriorationof the fusible wire by corona discharge and of interrupting the wholerange of currents from the weakest to the maximum currents guaranteed.

Having now particularly described and ascertained the nature of my saidinvention and in what manner the same is to be performed, I declare thatwhat I claim is:

1. In a high-tension high-power cartridge fuse having an elongated body,a tubular support of insulating material disposed substantiallyconcentrically within the body and extending the full length thereof;and a uniform-section continuous fusible wire having a part wound uponsaid support and a part within said support, whereby said wire isadapted to start fusing at one extremity and continue melting to theother extremity thereof.

2. In a high-tension high-power cartridge fuse'having a cylindrical bodypermeable to gases created therein, an insulating tubular supportpermanently disposed inside the body and extending the whole lengththereof, and a continuous uniform-section fusible wire partly wound overa portion of the support and partly extended within the remainingportion of the tubular support concentrically and parallel theretothrough an aperture provided in said support, whereby when said wire isoverloaded electrically it starts melting at one extremity and keeps onmelting it to the other extremity.

LOUIS JOSEPH SAUDICOEUR.

